Boiler



May 9, 1933. L.. DAVIDSON 1,908,125

BOILER Filed July 20, 1931 3 Sheets-Sheet l May 9, 1933.

L. DAVIDSON BOILER Filed July 20, 1931 3 Sheets-Sheet 2 www May 9 1933 l.. DAVIDSON v 1,908,125

BOILER Filed July 20, 1931 5 SheetS-Sheet 3 www Patented May 9, 1933 UNITED sra'res Louis mivinson,` on PILADELrHIA, rnNNsYLvANIn, Assieivon ToA MNA KAUFFMAN, on PHILADELPHIA, PENNSYLVANIA :coman Application mea July 2o, 1931. serial No. termici` lily invention relates to boilers which are used in generating steam or heating water, and relates particularly to that type ot boilers whichis ordinarily employed tor heating purposes.

Boilers of this type are commonly con structed" from castings, and, as is well known, castings are usually'ibeavy and do not readily adapt themselves to the constructions which are some times desirable from the standpoint ot economy and eiiiciency in .heating apparatus. In particular, my invention has to d o with the combustion chamber of a boiler, and I have found that by properly designing the combustion chamber, both the tire box and the iiue leading therefrom may be made from sheet metal, ths reducing materially both the cost oi' manufacture and the weight of the boiler, without substantially reducing the strength. It is one of the objects ot my invention, therefore, to eitect` economy inthe cost ot manufacturing such boilers, and to decrease their weight. A further object ot my invention is to simplify the entire boiler con-L struction, particularly the construction and arrangement of thecoinbustion chamber. It is alsoan object of my invention to improve upon the construction ot the flue leading trom the lire box outwardly through the fluidchamber. This simplification I bring about by so constructing the iiue that it is substantially in the form ot a flattened tube reversely bent upon itselt` to produce a tortuous passage for the gases ot combustion, such passage heilig comparatively tree from obstructions to the flue gases and providing an extensive heating surface for the water in contact therewith. y y

Without mentioning `further objects ot my invention at thislpoint, additional objects will be apparent from the detailed description which follows. 4In order that my invention may be readily understood and its practical advantages fully appreciated, rer"- crence should be made to the accompanying drawingsgwherein I have illustrated various modifications in which Vmy invention may be embodied In the drawings:

Fig. 1 is a vertical longitudinal View of a boiler in which one form of my invention is embodied; i

Fig. 2 is a transverse sectional view taken 55: onthe line 22 of Fig. 1;

Fig. 3 is a vertical side view of oneof the end plates for the combustion chambeii of the boiler shown in Figs.` l and 2; i

Fig. 4 is a view of the collar inserted be-V l tween the outer casing of the boiler and the Hue to form a flue cleaning outlet.

Fig. 5 is assembly view `of the boiler shown in section in Figs. 1 and 2;

Fig. 6 is a vertical longitudinal view of d5- a modiiied form of my invention showing the manner in which theV combustion chamber may be made ot castings; i

Fig. 7 is a transverse sectional view taken on the line 7 7 of Fig. 6; e i. i.

Fig. 8 is a vertical longitudinal view ofV a further modification of my invention in which the tire box is made ofV castings andr the iiue is made of sheetmeta'l;

Fig. 9 is a `longitudinal sectional view "is taken on the line 9-9 of Fig. 6; i

Fig. 10 is a detailed view showingth'e manner in which the line may be made from' metal tubing; l i

Fig. 11 is a vertical view of an upright' s" cylindrical boiler in which my invention is embodied;

Fig. l2 is a transverse` sectional view tak-V en on the line 1212 of Fig. 11; l

Fig. 13 is a transverse sectional view taken on the line 13H13 of Fig. 11;

Fig. 14 is a vertical longitudinal view ofi a still further modification in which my in#` vention is embodied; and

Fig. 15 is a transverse Vsectional View taken on the line 15-15 of Fig. 14.

In the boiler to which I apply my in'` vention I provide an outer casing made" of sheet metal, the side and `top walls of which are formed from a single continuous memberA l bent into substantially the shape Vof an" inverted U. End walls 2 and 3, likewise* made of sheet metal, are suitably secured' to the member l by welding or otherwise; l

lVithin the outer casing of the' boiler If 100 provide a combustion chamber comprising a fire box 4 and a flue 5 leading upwardly therefrom. The front wall of the fire box 4 is provided with a suitable opening at 6 within which a rim 7 is secured to thus provide an opening through which fuel may be supplied tothe tire box. The outer end of the rim 7 is suitably secured within an opening 8 of thefront wall 3 of the outer casing of the boiler, and the fuel opening may be closed by means of a door 9.

The combustion chamber disclosed in Figs. 1 to 5 of the drawings comprises essentially three sheet metal members.V One of these members is bent at right angles to form the front wall of the lire box and the upper wall thereof, and is then reversely bent on itself a number of times to form the bottom wall of the flue, after which it continues as `theupper wall of the flue outlet. As shown in Fig'. 1 of the drawings, this member includes. the vertical portion 11 forming the front wall of the tire box, and bends rearwardly at 10 to form the upper wall 12 thereof. This sheet metal member then turns upwardly, as at 13, and is reversely bent upon itself a number of times, as at 14,.to form the lower wall of a tortuous passageway for the flue. gases. The Vbend between the vertical portions 13 and 14 is preferably curved, as shown at 15, and the walls 13 and let are spaced from each other to provide agwater chamber therebetween. The number of the reverse bends in the lower wall of the flue will depend upon'the size vof the boiler. The construction will be such,-V however, that after a sufficient number of reverse bends have been provided the sheet metal member forming the front and top walls of the fire box and the lower wall ofthe flue turns upwardly, as at 17, in spaced, relation to the front wall 3 of the outer casing ofA the boiler, whereupon this member turns rearwardly to form the upper Wall of the Hue outlet as shown at 18.

As I have embodied myinvention in the boiler shown in Figs. 1 to 5, I preferably construct the rear wall of the ire'box, the upper wall of the Hue, and the lower wall ofthe flue outlet from one continuous piece of sheet metal. This sheet metal member comprises the vertical back wall of the lire box 19 extending upwardly lin spaced relation to the wall 2 of the outer casing, whereupon it is reversely bent upon itself a suitable number of times to form, with the lower reversely bent wall and the side walls hereinafter described, a tortuous passageway for flue gases. The member forming the rear wall 19 of the ire box is curved as indicated-zat 21 and thence reversely bent upon itself as indicated at 20. It will be observed that this construction provides a series of proJections and depressions in both the upper and lower ue walls, the projections of one being arranged within the depressions of the other to thus form a continuous, unobstructed passageway. It will be observed further that the construction is such that all bends in the passageway are of curvilinear formation, a construction which materially assists the passage of the flue gases therethrough.

After beingrreverselybent upon itself a sufficient number of times to form the upper wall of the mainl portion of the flue 5, the sheet metal member is bent rearwardly as yat 22 in parallel and spaced relation with respect to the upper wall 18 to form the flue outlet.

vThe side walls of the combustion chamber are preferably formed from a punched sheet metal member 23 as shown in Figs. 2 and 3 of the drawings. This sheet metal member is so formed as to provide a side wall 24- for the fire box 4, a side wall 25 for the flue 5 and a side wall 26 for the flue outlet. It will be understood that two o f the members 23 are provided, rone for each side wall of the combustion chamber, and that these side walls may be secured in position with respect to the two sheet metal members forming the front, rear and top walls of the fire box and the top and bottom walls of t-he flue by welding or otherwise as may be desired.

The flue outlet extends through a suitable opening 27 in the rear wall 2 of the outer casing of the furnace. Opposite the opening 27 an opening 28 may be provided in the front wall 3 ofthe outer casing, and in the opening 28 the forward end of a flattened tube 29 maybe secured and may be connected to the flue outlet as at 30 to provide means whereby the flue outlet may be cleaned. A closure 31 of any suitableform may be provided for this cleaning outlet.

As shown in Fig. 3 of the drawings the lower ends of the side wall 25 for the iiue 5 are cut away as yat 32 to receive a substantially D-shaped'coll'ar 33 secured to the side wall 25 and inserted in an opening in the wall of the outer casing 1, thus providing an opening from the exterior of the boiler whereby the lower reverse bends of the fluev may be cleaned. It is to be understood thatvthesecleaning openings are provided on both sides of the furnace for each of the lower bends of the Hue. These openings may be closed by covers 35 hinged as shown at 34, or by some other suitable means.

In order that the flue proper may be supported in position I provide a number of metallic stay rods or blocks 36 welded or otherwise secured in place between the upper wall 12 of the fire box and the lower bends of the flue. Similar' stay rods 37 are welded or otherwise secured in place between the upper bends of the flue proper and the lower wall 22 of the flue outlet.

A strip of sheet metal 38 is Welded or momes otherwise secured around the bottom ofthe walls of theouter casing and the bottomof the sidewalls `of the fire `box to close the intervening water chamber.`

A nipple 39'is secured in the top of the outer casingapreferably near the front thereof, for the attachment of suitable gauge 40, and a similar nipple 41 is providedin orderthat asafety valve 42 may be attached to the boiler.y An inlet for the fluid chamber\is`.provided at 43 and a suitable outlet maybe provided as at 44.`

The boiler heretofore described maybe provided with abase 45 providing an ash pit 46 having an opening 47 through which ashes may be removed. In ease the fuel used with my furnace is wood or coal any desired arrangement of grate bars, as indicated at 48, may be provided. It will be understood, however, that other kinds of fuel, such as oil or gas, may be used if desired;

In the modification of my invention il` lustrated in Figs. 6 and 7 of the drawings,

' the tire box 4 is shown as made from sheet metal, although it may be made from eastings. Preferably the fire box 4 may be made in two substantially U-shaped sections, and the open ends of the U-shaped sections maybe welded or brazed together. In constructing the fire box in this manner itV will be observed that the upper wall is formed by a part of the casting of the flue 5. The form and arrangement of the flue 5 do not differ essentially from the form and arrangement of the flue heretofore described in connectionwith the construction shown in Figs. 1 to 5. In the process of casting,` connectingportions V36 are pro vided for supporting the lower bendsl onv the upperwalll 12 of the fire box, and connecting portions 37" are likewise provided for supporting the flue outlet upon the `upper bends 21 of the flue proper.

In this modification, as in the construction shown in Figs. 1 to 5, it will be observed that the flue is substantially inthe form of a" flattenedtube reversed upon itself with curved bends, thus providing substantially parallel, unobstructed passages for the flue gases. The fiuecasting is provided with a shoulder 49 aroundits bottom edge for supportingit* upon` the upper edge of the fire box, and the oint thus formed may be sealed in any suitable manner.- Y

In themodificationof my invention shown inlllig.` 8 IhaveI disclosed the lire box 4 formed of a` single, integral casting, and the flue leadingtherefrom is made from flattened metal tubing. As shown in dotted lines at50fin Fig. 10, the tubing from which the flue is made may be circular in cross section and is flattened as shown at 51 into such. form asmay be desirable. It will be preferable to expand 'the flattened tube 'bends where it joins with the lire box 4 at 52 to provide a tapered opening into the flue. A flattened tube of this type may be reversely bent upon itself at intervals with comparative ease to provide a tortuous pas- N sageway for the flue gases, and the rounded bends at 21 are free from any obstructions which would hinder the passage of the gases therethrough. The adjacent walls Vof the reversely'bent portions will be spaced from eachother to provide a fluid chamber as heretofore described in connection with Figs 1 to 5^. Y Y

I n the modification of my invention illus# trated in` Figsll to 13 of the drawings I have shown an upright boiler of the eylin drical type, preferably made of sheet metal, and comprising the side wall 54 having a top 55 welded or otherwise suitably secured thereon. Within the bottom of' the outer easing thus vformed I provide a fire box 56 which may be made in the form of a' dome shaped casting. This fire box is provided with an outlet 57 into a flue 58 which may be constructed in the manner hereinbefore described with respect to the modification of my, invention illustrated in Fig. G, er in accordance with the modification illustrated in Fig. 8` of the drawings. In either case it portions of which are spaced from each oth-` er to provide an intervening fluid chamber. It will` also be understood that the reverse inthis passageway are throughout their length, as heretofore described, in order to obviate as much as p'ossible any obstruction to the passage of flue gases. y

Suitable openings for cleaning the flue may be provided as indicated at 59, these openings being closed by suitable lcovers 60. The lue may be supported upon the iire box 56 by means of a plurality of stay rods 36 secured interinediate the upper wall of the fire box 56 and the adjacent wall of the flue 58. Similar stay rods 37 may be provided to support the flue with respect to the vertical `wall 54 of the outer casing of the boiler.

Inthe modification of my invention illustrated inA Figs. 14 and 15 of the drawings I have shown a cylindrical boiler of the horizontal type having an outer wall 61, preferably made of sheet metal. wall 62 and a rear wall 63 are suitably secured to the cylindrical casing Gl by riveting orwelding as may be desired, and the outer casing thus formedis supported upon the base 64.

`Mounted within the lower part of the out er casing is a fire box 65, preferably of cylindrical shape and supportedin spaced relacurvedersl A front tion to they outer casing by means of stay bolts 66. The rea-rxvall 67 of the fire box may be secured in any suitable manner, as by riveting or welding, to. the cylindrical casing forming the side walls of the lire box, and the front wall 68 may be similarly secured in place.

A suitable opening 69 is provided in the front wall 68 through which fuel may be placed in the re box, this opening being closed by a door 70. A similar opening 71 may be `provided for the removal of ash from the fire box, this opening being closed by a suitable door 72.

A flue 73, preferably madevfrom aflattened tube as hereinbefore described, opens outwardly from the fire box as indicated at 74, and after being reversely bent uponY itself to form a plurality of substantially parallel passages vthis flue passes outwardly through the outer casing as at 75.V v'Each of the bends connecting the adjacent parallel passageways is in the form of a continuous curve, as heretoforedescribed, and the upper bends in the flue may be provided with outlets 76 for flue gases. These outlets may open directly into the main flue outlet 75 through suitable pipes or passages 77, or they may open'through pipes 78 to a pipe 79 opening into the main flue outlet 75 at 80.

Aflue cleaning opening 81 located at the front of the boiler gives access to the flue outlet 75, and this opening may be closed by the suitable cover 82. Y

From the above detailed description of my invention, as embodied in the various modifications referred to, it will be apparent that I have devised a boiler that is of simple construction, efhcient in use, and may be made at small cost as compared with boilers which have heretofore been used for similar purposes. It'will also be apparent that I have devised a combustion chamber for such boilers that is simple to manufacture, and inexpensive as compared with constructions heretofore used. It will furthermore be apparent that I have devised a flue structure that is exceedingly simple topmanufacture, inexpensive in comparison with similar structures heretofore known, and one that provides an extended heating sur face and is at the same time free from obstruction to the passage of flue gases. It will also be clear that 'the construction of my improved flue is such that the current of flame and flue gases, when passing therethrough, remains intact and undivided, thus functioning more efficiently in heating the fluid in contact therewith. It will be clear furthermore that, by my improvement, lI provide a boiler in which the combustion chamber is entirely surrounded by the fluid to be heated, thus providing a maximum heating surface as compared with boilers heretofore used.

wall.

vin the upper wall of others.

' While'I have described various modifications of my invention, it will be understood that these modifications merely illustrate desirable ways in which my invention vmay be put into practice, and other modifications may be resorted to Without departing from the spirit of my invention vas set out in the appended claims. I have shown the fuel door of the various modifications of my boiler construction located in the front Wall. It` `will be understood, however, that this door may, if desired, be placed in the rearv I have also shown the flueoutlet in the rear wall'of various modifications, and This outlet may be arranged adjacent the front of the boiler if desired, either in the upper wall or in tl1e.front wall.`

Having thus described my invention, what I desire to secure by Letters Patent is:-

1. In a boiler of the character described, an outer casing, a combustion chamber therein and spaced therefrom to provide a fluid chamber, said combustion chamber comprising a fire box and a flue leading therefrom, said flue comprising a flattened tube reversely bent'upon itself to form a series of substantially parallel, curvilinear-ly connected passages spaced from each other to provide a fluid'chamber between successive passages.

2. In a boiler of the character described, an outer casing, a fire box therein and spaced therefrom to provide a fluid chamber, a flue leading outwardly from the fire box through said'fluid chamber, said flue comprising a flattened tube reversely kbent upon itself to form a series of substantially parallel, curvilinearly connected passages spaced from each other. f

3. In a boiler'ofl they character described, a substantially cylindrical-outer casing, a fire box therein and spaced from the walls thereof to provide a fluid chamber, a flue leading outwardly from the fire box through said fluid chamber to the exterior of the casing, said flue comprising a flattened tube reversely bent upon itself to form a series of substantially parallel, curvilinearly connected passages spaced from each other.

4. In a combustion chamber for a boiler of the character described, a fire box, a flue leadingoutwardly therefrom comprising a flattened tube reversely bent upon itself to form a series of substantially parallel passages spaced from each other to provide a fluid chamber between successive passages, the successive vpassages being connected to each other by a curved outer wall to permit flue gases 'to readily pass therethrough.

5.-'I-n a combustion chamber for a boiler of the character described, a fire box, a flue leading outwardly therefrom comprising a flattened tube reversely bent upon itself to form av series .of substantially parallel and vertically arranged passages spaced from each other to provide a fluid chamber between successive passages, the upper bent portions connecting successive passages being provided with outlets for flue gases.

6. In a boiler of the character described, a substantially cylindrical outer casing, a iire boX therein substantially cylindrical in shape and spaced from the outer casing to provide a fluid chamber therebetween, a flue leading outwardly from the iire box through said fluid chamber to the exterior of the casing, said ilue Comprising a flattened tube ereversely bent upon itself to form a series of substantially parallel passages spaced from each other.

In testimony whereof, I have signed my naine to this specification.

LOUIS DAVIDSON. 

